Jewish existentialism is a category of work by Jewish authors dealing with existentialist themes and concepts (e.g. debate about the existence of God and the meaning of human existence), and intended to answer theological questions that are important in Judaism. The existential angst of Job is an example from the Hebrew Bible of the existentialist theme. Theodicy and post-Holocaust theology make up a large part of 20th century Jewish existentialism. Examples of Jewish thinkers and philosophers whose works include existentialist themes are Martin Buber, Joseph B. Soloveitchik, Lev Shestov, Benjamin Fondane, Franz Kafka, Franz Rosenzweig, Hans Jonas, Emmanuel Levinas, Hannah Arendt, Rabbi Abraham Joshua Heschel, and Emil Fackenheim. Jewish existentialism finds its roots in both the traditional philosophical school of existentialism and the peculiarities of Jewish theology, Biblical commentary, and European Jewish culture. Existentialism as a philosophical system grew as a result of the works of such non-Jewish thinkers as Søren Kierkegaard, Friedrich Nietzsche, Albert Camus, and Martin Heidegger. The Books of Ecclesiastes and Job, found in the Hebrew Bible and often cited as examples of wisdom literature in the Hebrew Biblical tradition, both include existentialist themes. The Book of Job tells the story of Job, who is beset by both God and Satan by many hardships intended to test his faith. He ultimately keeps his faith and receives redemption and rewards from God. The Book of Job includes many discussions between Job and his friends, as well as between Job and God concerning the nature, origin, and purpose of evil and suffering in the world. The Book of Ecclesiastes is broader in scope and includes many meditations on the meaning of life and God's purpose for human beings on Earth. Passages in Ecclesiastes describe human existence in such terms as "all is futile" and "futile and pursuit of wind". Much Biblical scholarship and Talmud exegesis has been devoted to exploring the apparent contradiction between the affirmation of an all-powerful God's existence and the futility, meaningless, and/or difficulty of human life.